Drying cylinder



Apr.. 24, 1923. wifi; m 11111` E. HUTHWN@ DRYING CYLINDER Filed Feb. 18, 1922 ZVSheS-Sheei l M Il WVM Egp no Mmm, 24, W23.. MAMJM 1E. HUTMIIN DRYING CYLNDER Filed Feb. 18, 1922 2 Sheets-Sheet 2 application tiled liehruaryn ttt, 192%. tlferial No. tllhtlh.

` accompanying drawing.

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'lhis invention relates to internally heated drying cylinders which impart the heat to and drythe material in contact with the external surface thereof,'and the invention is particularly concerned with drying cylinders of this type employed in paper malt-I ing machines-wherein the moist paper web or sheet passes around a series of such drying cylinders, rotated at suitahle speed, and is dried thereby., The heating of the cylinders is effected by the introduction of steam therein, and in the drying operation the steam is condensed and the condensed water is continuously removed from the cylinder to prevent the same from collecting in too great quantity. ln the rotation of the cylinder at the speed employed in practice, the action of centrifugalforce throws the water outwardly against the wall of the cylinder and it spreads thereover in the form of a film, which acts to some extent as a heat 'insulator and thereby interferes with and retards the effective conduction of the heat ofthe steam through the cylinder wall.

` ln this way much ofthe heating effect ofthe tion,and the invention consists in providingsteamon the cylinder is lost, and the edi'ciency of the drying cylinder reduced, lli/ly invention aims to overcome this ohjectionable acthe interior of the cylinder with a series of heat conducting projections of such form and relative arrangemenh that notwithstanding the presenceof the water 1 zo under the conditions mentioned, the heat conducting projections will loe exposed to direct contact with the steam, and the heat of the latter will he diffused by the projections throughout the wall of the cylinder and external active surface of the same. These projections may be of different forms and may he variously arranged without departing from the spirit of the invention,- the main requirements. being that they shall be of such height as. to entend through and 4`loeyond the water distributed over the surface'of theeylinder so that their terminal portions will he ea- 55 posed to direct contact with the steamy and they shall be in such proximity to each other as to diffuse the heat'in a -substantially uni- Y form manner' throughout the external surface of thecylinder, and not in Spots or @d separated areas such as would dry the paper in strealrs or at intervals. ln the accompanying drawings l have shown two different embodiments of the invention byway of exampleyhdtuitwwill lhe '65 manifest to the skilled mechanic that the invention may he embodied in other forms; and further it will be understoodthat the invention is not limited to any particular form or construction of the parts., except in to so vfar as such limitations are specified in the claims. y

ln the accompanying drawings: Eig. l is a longitudinal sectional elevation of a drying cylinder having my inven- .l5 tion emhodied therein in its preferred form. lig. 2 is a fragmentary sectional view of a portion of the cylinder of Fig. l, showing how the heat conducting projections are eaposed through the water hlm to the direct d@ contact of the steam. y 3 is a. cross-sectional elevation on the line 3-3 of Fig. l., l

lfig. l is a view similar to lfig.. l showing the heat conducting projectionsl in modified ttt A form.

Referring to the drawings:

Referring to figs. t and Q it designa a hollow metal drying cylinder., such as are v employed in paper making machines to dry ou the paper web. dt its opposite ends the cylinder is provided with journals B-B adapted to be mounted in suitable bearings for-supporting the cylinder rotatably, and one of these journals is made hollow for-the at entrance of the heating steam and for the removal of the water of condensation, allas is well known to those skilled in this art. ln the rotation of the cylinder at the speed employed in practice. the condensed Awater loo is thrown outwardly by centrifugal force in the form of a film which overspreads the inner surface of the cylinder, and as the presence of this water film prevents direct contact of the steam with the surface of the cylinder, the conduction ofthe heat of the steam to the outer surface of the cylinder is greatly retarded and its drying efficiency is reduced. In accordance with my invention this heat insulating effect of thelwater of condensation is obviated by providing on the interior of the cylinder wall, a series of heat conducting projections C, which in the embodiment of the invention shown in Figs.

1 and 2 are in the form of helically arranged ribs formed integral with and projecting inwardly from the cylinder shell. These 'ribs are of a height or radial extent sufiicient to extend through the water overspreading the cylinder wall, which water collects in the channels or spaces between the ribs, so that the inner terminal portions of the ribs will be exposed to direct contact with the heating steam as shown in Fig. 2. The ribs will act therefore to conduct the heat of the steam through the cylinder wall to its outer surface and,` will thus secure the maximum heatingefiiciency of the steam on the cylinder. The ribs are in such proximity to each other that the heat will be diffused uni'- formly throughout the lexternal dryingsurface of the cylinder, and the paper will be dried by said surface throughout its extent and at all points in its area and not in streaks or 'spots as would result if the heating projections were spaced apart from each other to an undue extent.

I By the helical arrangement of the ribs, the water collecting in the channels or spaces between them will be conveyed in the rotation of the cylinder. toward one end of the same so that it can be continuously removed by suitable means. To effect the removal of the Water, I, in the present instance, provide the cylinder at the end of the ribbed portion, with a water receiving chamber D with which the channels between the ribs communicate, and I fix to the head of the cylinder, water scoop pipes E having their outer ends open and extending into the chamber and having their inner ends connected with a hollow hub F fixed to the end wall of the cylinder and communicating with the inner end of a discharge pipe G which extends outwardly through the hollow journal and discharges at the outside.. Obviously other forms of devices for effecti the discharge of the water of condensation may be employed without departing from the spirit of my invention. The heat conducting projections instead of being in the form o f ribs as just described, may be in the form of localA projections or lugs C as shown in Fig. 3 where it will be seen that the lugs are arranged in helical rows separated from each other by helical channels in which the water will collect and be conveyed to the end of the cylinder similar to the conveying action of t e ribbed formof projections first described.A So also the heat conducting projections may be in other forms and arrangements 'provided that they will be exposed to direct contact with the steam and will be in such proximity to each other as to diffuse the heat throughout -the surface of the cylinder as described.

Having thus described my invention, whaty I claim is:

l. A drying cylinder adapted to have heating steam introduced therein, said cylinder being providedv on'its interior with heat conducting projections formed and arranged to be exposed to direct contact with the steam and to diffuse the heat ofthe steam throughout the. external surface of the cylinder'.

.2. A drying cylinder adapted to have heating steam introduced therein, said c 1- inder being provided on its interior with heat conducting projections of a height to extend through the film of condensed water, and arranged in such proximity to each other as to diffuse the heat of the steam uniformly throughout the external surface of the cylinder.

3. A drying cylinder adapted to have heating steam introduced therein, said cylinder being provided on its interior with heat conducting projectlons with s aces be to diffuse the heat of the steam uniformly throughout the external surface of the cylinder. Y

4. A drying cylinder vadapted to have heating steam introduced therein, said cylinder being provided on its interior with helically arranged heat conducting projections With spaces bet-Ween them for the water of condensation, said projections being` exposed to direct contact with the steam and ada ted to diffuse the heat of the steam uniform y throughout the external surface of the cylinder.

5. A- drying cylinder adapted to have heating steam lintroduced therein, said cylinder being provided with helically arranged heat conducting ribs with s aces between them to receive the water o condensation and convey the same to the end of the cylinder, said ribs being of a height to extend through the water film and be cxposed to direct contact with the Steam, and being in such proximity to each other as to diffuse the heat of the steam throughout the external surface of the'cylinder.

6. A drying cylinder adapted to have heating steam introduced therein, said cylinder being provided on its interior with helicallyY arranged heat conducting projec- 

